I had the tank strapped in and did not like the way it was holding. I decided I wanted a hard mount and came up with this 1/8 inch flat bar, 2 - 10 inch battery hold down kits and some hardware to screw it all together.

I know the sender should be 1 inch from the bottom, so I think in our boats below that should work. 1/2 to 3/4 inch. Further off the bottom means less chance to pickup crud. You should check around on getting another tank. You may be able to find someone dismantling a M that has a tank they would se...